Fire doors are effective during fires due to their unique structure and materials. Typically, they are composed of door frames, door panels, fire-resistant locks, door closers, and fire-resistant glass if applicable. The core lies in the door panel material, which is usually made of high-temperature-resistant, flame-retardant steel or wood (treated for special purposes). Inside, they are filled with fire-resistant insulation materials like aluminum silicate fibers and rock wool. These materials maintain structural stability under high temperatures, blocking heat transfer and flame spread.

With technological advancements, fire doors are moving towards intelligence. Modern fire doors not only provide basic fire prevention capabilities but also integrate intelligent control systems, such as automatic fire alarm interconnection and remote control switching. In the event of a fire, fire detectors can quickly respond, transmitting signals to the control center, and automatically or manually initiating the closure mechanism of the fire doors to prevent the spread of the fire. Additionally, some fire doors are equipped with emergency escape locks to ensure that personnel can疏散 quickly in emergencies.

The working principle of fire doors is based on a multi-layered protection mechanism. Their sealing performance is crucial, achieved through the design of seals between the door frame and door leaf, preventing smoke and heat from permeating. Additionally, fire doors can withstand high temperatures for a designated period (typically 90 minutes for grade A, 60 minutes for grade B, and 30 minutes for grade C) without being damaged, thus gaining precious time for personnel evacuation and fire rescue. Furthermore, fire doors are usually designed to be either normally open or normally closed. Normally open fire doors require an electromagnetic release device to automatically close upon receiving a fire signal, while normally closed fire doors rely on door closers to maintain their closed state, reducing safety hazards caused by human error.

Fire doors are not only a strict requirement of building codes, but also a safeguard for life safety. In residential areas, they can prevent fires from spreading from one unit to the entire building; in public places such as malls, they are crucial for defining safe zones and providing safe evacuation routes for people. Therefore, it is the responsibility of every property manager and resident to regularly inspect the integrity of fire doors and ensure they are in good working condition.